Method for making aquatic pools and in particular for swimming pools

ABSTRACT

The invention concerns a method for making aquatic pools such as swimming pools, which consist in covering the panels ( 1 ) of a cavity with concrete. The invention is characterised in that it comprises the following steps: preparing a mixture of cement ( 2 ), sand ( 4 ) and fibres ( 3 ); transferring said mixture to a spray nozzle; simultaneously spraying said mixture and water on the wall to be covered, with the spray nozzle ( 12 ). The invention also concerns a pool, in particular for swimming obtainable by using said method. The invention is applicable to aquatic pools.

[0001] The present invention relates to a process for the production of aquatic pools consisting in covering the walls of a cavity with concrete.

[0002] It also relates to a pool particularly for swimming, adapted to be produced by using this process.

[0003] In the field of the production of swimming pools, there is generally produced a cavity in the ground adapted to receive the necessary volume of water. The walls of the cavity (side walls and bottom) are covered with concrete.

[0004] Conventionally, there is first erected an armature of steel about which is poured the concrete. A lining is also necessary to carry out covering to a regular thickness.

[0005] Such a production technique has various drawbacks.

[0006] In the first place, pouring the concrete represents a relatively long step requiring substantial labor.

[0007] Moreover, a steel armature is necessary which increases the cost of production.

[0008] Still further, the steel armature is not always easy to emplace, which is troublesome to produce pools whose shape is irregular.

[0009] It has already been proposed to reinforce the concrete by means of fibers such as steel fibers or polypropylene fibers so as to avoid recourse to a steel armature.

[0010] However, it has not been possible until now to use such concrete reinforced with fibers in the production of pools.

[0011] The present invention permits overcoming the drawbacks in the present production techniques and avoids the prejudice according to which the use of fiber concrete is impossible in the field of the production of pools.

[0012] To carry out such a production, the invention proposes different steps.

[0013] Preferably, a spraying of fiber concrete is carried out on the walls to be covered with a high flow rate.

[0014] Thus, it has been discovered that the use of a high flow rate permits maintaining the cohesion of the fibers and of the concrete and hence obtaining a final fiber content in the hardened concrete that is as high as possible.

[0015] It has been discovered that the use of a lower flow rate (of the order of 1 to 2 m³ per hour) gives rise to a dispersion of the fibers in the atmosphere before the concrete reaches the wall to be covered.

[0016] Another advantage of the invention is to cover in a single step all the necessary thickness. A single passage can thus be carried out on the wall of the pool.

[0017] Another object of the invention is to provide a pool having characteristics of mechanical resistance at least as favorable as those of reinforced concrete. To do this, a precise mixture and particular proportion of fibers is proposed.

[0018] Another object of the invention is to provide reinforcing fibers of a particular form.

[0019] Other objects and advantages will become apparent from the course of the description which follows.

[0020] The present invention relates to a process for the production of aquatic pools such as swimming pools, consisting in covering the walls of a cavity with concrete, characterized by the fact that it comprises the following steps:

[0021] preparation of a mixture of cement, sand and fibers.

[0022] transfer of said mixture to a spray nozzle.

[0023] simultaneous spraying of said mixture and water on the wall to be covered, by the spray nozzle.

[0024] This procedure can comprise the following steps:

[0025] spraying on the wall at a flow rate of more than 6 m³/h.

[0026] using a mixture comprising between 30 and 70 kg/m³ of fibers.

[0027] fiber are steel or polymeric material.

[0028] the mixture comprises between 17 and 22% of cement, by weight.

[0029] there are used fibers whose length is from 3 to 5 cm and whose ends are bent to form two wings.

[0030] prior to spraying, there is projected a lining of wattle on the wall to be covered.

[0031] The invention moreover relates to a pool particularly for swimming adapted to be produced by using the process according to the invention and characterized by the fact that its walls, at least the side walls, are covered with a composite material constituted by at least one layer of wattle embedded in concrete based on cement, sand and fibers.

[0032] The accompanying drawings are given by way of indicative example and are non-limiting. They show a preferred embodiment according to the invention, they permit easy comprehension of the invention.

[0033]FIG. 1 is a schematic view of the principal steps of the process for production used.

[0034]FIG. 2 shows a particular embodiment of the fibers incorporated in the concrete mixture.

[0035] As shown schematically in FIG. 1, the wall 1 of the pool is to be covered with a mixture constituting the concrete.

[0036] The production of this covering of concrete is carried out by means of spraying with concrete.

[0037] According to the invention, there is first prepared and constituent mixture of the concrete comprising fibers 3, cement 2 and sand 4. The mixture is carried out by means of a mixture 5 and then directed toward a hopper shown at 6 in FIG. 1.

[0038] Via the hopper, the mixture arrives at a rotor 7.

[0039] At this point, a compressor 8 is used to increase the speed of the mixture so that it arrives at a high flow rate at the spray nozzle 12.

[0040] The acceleration of the mixture is carried out by means of a compressor 8 supplying compressed air to the rotor 7 through a tube 9.

[0041] At the outlet of the rotor, the circulation of the mixture toward the projection nozzle 12 is carried out by a transfer tube 10.

[0042] Moreover, a water tube 11 is present to convey water also under pressure (preferably by the same compressor 8).

[0043] The water and the mixture meet at the spraying nozzle 12.

[0044] Thus, the production is carried out dry, up to the nozzle 12.

[0045] At this point, spraying at a high flow rate is carried out.

[0046] Preferably, the spray flow rate will be at least 6 m³ per hour.

[0047] In this way, there is obtained a definitive quantity of fibers in the sprayed concrete, which will be very high.

[0048] Reduced loss into the atmosphere is noted, even with the use of fibers of polymer material and particularly polypropylene.

[0049] As to this, the fibers will preferably be either steel, or of polymeric material such as polypropylene.

[0050] Moreover, a fiber content of 30 to 70 kg/m³ in the mixture is suitable to obtain a wall of good strength.

[0051] Moreover, the mixture can comprise between 17% and 22% of cement by weight.

[0052] So as to obtain good cohesion of the mixture and particularly of favorable interaction between the matrix constituted by the assembly of the cement and sand and reinforcing fibers, these latter will preferably have a length of 3 to 5 cm and will have ends 14 bent so as to form two wings.

[0053]FIG. 2 shows this particular embodiment in which two ends 14 are bent.

[0054] A composite layer is thus constituted on the wall 1 of the pool.

[0055] This layer can also comprise at least one layer of wattle 13 constituting a sort of lining.

[0056] The lining of wattle is positioned before spraying.

[0057] The layer of wattle thus incorporated facilitates the holding in position of the sprayed concrete and ensures the regularity of spraying.

[0058] To show the performance of the present production process, let it be indicated that for a content of 50 kg/m³ of steel fibers in the mixture, there is obtained in situ a content of forty-six kg/m³ of these same fibers. It will thus be seen that there is very little loss from spraying.

[0059] Moreover, it has been discovered that the movement of the walls under a load (particularly under the load of water pressure within the pool) is less for fibrous concrete sprayed according to the present invention, than for reinforced concrete according to the prior art.

[0060] In this way, the risk of deformation of the pool once filled with water, is less with the process of production of the invention than with conventional processes with reinforced concrete.

[0061] The invention also relates to a pool adapted for the process of the invention. Particularly, the pool has its walls covered with a composite material constituted by at least one layer of wattle embedded for example by the process of the present invention, in a concrete based on cement, sand and fibers. REFERENCES  1. Pool wall  2. Cement  3. Fibers  4. sand  5. Mixer  6. Hopper  7. Rotor  8. Compressor  9. tube 10. Transfer tube 11. Water tube 12. Nozzle 13. Wattle 14. End 

1. Process for the production of swimming pools, consisting in covering the walls of a cavity with concrete, characterized by the fact that it comprises the following steps: preparation of a mixture of cement, sand and fibers. transfer of said mixture to a spray nozzle. simultaneous projection of said mixture and water on the wall to be covered, by the spray nozzle.
 2. Process according to claim 1, characterized by the fact that spraying on the wall is carried out at a flow rate greater than 6 m³/h.
 3. Process according to claim 1 or 2, characterized by the fact that there is used a mixture comprising between 30 and 70 kg/m³ of fibers.
 4. Process according to any one of claims 1 to 3, characterized by the fact that the fibers are steel or polymer material.
 5. Process according to any one of claims 1 to 4, characterized by the fact that the mixture comprises between 17 to 22% by weight of cement.
 6. Process according to any one of claims 1 to 5, characterized by the fact that there are used fibers whose length is from 3 to 5 cm and whose ends are bent to form two wings.
 7. Process according to any one of claims 1 to 6, characterized by the fact that prior to spraying, there is positioned a lining of wattle on the wall to be covered.
 8. Pool, particularly a swimming pool, adapted to be produced by use of the process according to claim 7, characterized by the fact that its walls, at least the side walls, are covered with a composite material constituted by at least one layer of wattle embedded in a concrete based on cement, sand and fibers. 